Freeze fracture machines serve for the processing of frozen samples such as tissue samples. The frozen sample can be sectioned or fractured, by means of a knife, in a vacuum chamber of the freeze fracture machine. The vacuum chamber or vacuum serves in particular to eliminate water that could contaminate the sample. In addition, both the sample and the knife are cooled, usually with liquid nitrogen, so that the frozen sample does not become heated during processing.
A viewing window, through which the sample to be processed is visible, is usually provided in the freeze fracture machine or in the vacuum chamber thereof. A microscope can furthermore be provided, for example, if very small samples are to be processed.
A transfer lock, through which the sample can be introduced into or removed from the vacuum chamber without interrupting the vacuum, can be provided on the freeze fracture machine for the introduction and removal of a sample.
In order to introduce or remove a knife, for example in order to change a knife type or replace a contaminated knife, it has hitherto been necessary to break the vacuum, aerate the vacuum chamber, and change the knife via the viewing window or a corresponding door. It is disadvantageous here that as a result of the aeration and re-evacuation, the knife changing procedure takes a very long time. In addition, the entire vacuum chamber must be heated to room temperature so that the knife can be changed.
It is therefore desirable to describe a capability for faster and simpler changing of a knife and a sample in the context of a freeze fracture machine.